Pre manufactured structural panel consisting of a flame retardant external crust and an aeroboard core fabricated from laminations of uncompressed cardboard, impregnated by resin solutions recovered from post consumer thermoplastics

ABSTRACT

A premanufactured structural composite panel consisting of a cardboard core impregnated with resin solutions recovered from post consumer thermoplastics, and an impact resistant and flame resistant crust formed from Portland cement mortar or polymer cements formulated from said recovered resin solutions, particulates and fibres or fabric and decorated using coatings formulated from said recovered resin solutions. The flame retardant treatment includes ammonium, boron, phosphorous compounds for the cardboard and recovered resin solutions that demonstrate a flame retardant character.

REFERENCES CITED

[0001] References Cited Date Yr U.S. Pat. No. Author April 1895 536,993J. T. Allen Aug. 17 1923 1,541,163 Minache Jan. 24 1958 2,839,312 H.Serliner Jan. 1980 4,184,311 Rood Nov. 1981 4,300,322 Clark Apr. 19915,008,359 Hunter Jan. 7 1992 5,078,937 Ee/a Aug. 1992 5,140,086 Hunteret al Mar. 1994 5,292,391 Wallick Jul. 1994 5,532,458 Wallick Dec. 19965,580,922 Park et al 5,715,637 Mar. 24 1998 5,729,936 Maxwell J. Mar. 91999 5,880,243 Park et al Nov. 6 2001 6,313,423 Sommer et al Jan. 1 20026,335,376 Allen III et al 6,368,529

BACKGROUND OF THE INVENTION

[0002] The present invention relates to by products of post consumercardboard, paper and thermoplastics and in particular prefabricatedpanels formed by the impregnation and lamination of cardboard sheetsusing resin solutions recovered from post consumer thermoplastics.

[0003] The airspaces created by the corrugated sections of cardboard(corrugated container board) and the micro porosity of the paper presentin cardboard are critical structural characteristics that facilitatesthe impregnation and curing of the panels respectively.

[0004] The internal columnar spaces in the cardboard sheet stock aredrenched by the gravity flow of resin solution when said spaces areoriented vertically. Surface adhesive application and lamination ofdried internally drenched cardboard sheet stock forms panels with panelcores of appropriate thickness (called aeroboard). The curing of theresin solution is achieved by the forced circulation of hot air throughthe columnar air spaces present in the cardboard sheet stock. Drying maybe done in kilns or directed hot air streams under covered plasticsheets.

[0005] The quest for alternative uses for bulky wastes has led to arange of processes for recycling and reuse of paper plastics and paperproducts. A large number of outcomes are directed to the fabrication ofbuilding insulation materials in shredded molded and compressed forms.The bulk of these wastes continue to be burned or dumped in landfills.

[0006] Various methods of prefabrication of building panels have beendeveloped. U.S. Pat. No. 536,993 to J. T. Allen issued April 1895describes a method of forming panels from chips of stnre or clayembedded in a plastic material wherein interstices between the chips arepartially filled with sand. U.S. Pat. No. 2,839,312 to H. Serlinerissued Jun. 24, 1958 claims a structural panel consisting of highstrength concrete on both sides of a metal framework. The space betweenthe two high strength layers of concrete is filled with a lightweightlow strength concrete. U.S. Pat. No. 5,078,937 to Eela issued Jan. 7,1992 claimed a method to form a slab like product from fibrous materialsmixed in concrete.

[0007] U.S. Pat. No. 1,541,165 to Minache issued Aug. 17, 1923 describesa thin, three layered—load-bearing wallboard composite.

[0008] A number of patents have been directed at the production ofinsulation material U.S. Pat. Nos. 4,184,311 and 4,300,322 detailmolding and shredding and laminating techniques. Methods also employedvarious combinations of injecting, spraying adhesion and curingprocesses. The formulation of slurries of shredded waste material isalso commonly exploited.

[0009] The pervasive use of high temperatures and pressures in theprocessing of bulky wastes into remanufactured products is frequentlydescribed within the art. These conditions seek to achieve bothimpregnation, uniformity and heat catalyzed curing. Hunter in U.S. Pat.No. 5,008,359 prescribed temperatures above 150 degree C. and pressuresgreater than 3000 K Pa in the processing of cellulosic substrates withisocyanate impregnants. Hunter et al in U.S. Pat. No. 5,140,086prescribed the use of compatible organic solvents for the promotion ofuniform dispersion of the impregnant. The prohibitive costs of pressesfor these high temperature and compression operations however wouldcontribute significantly to increase their production costs.

[0010] Attempts were made by Wallick in U.S. Pat. Nos. 5,292,391 and5,332,458 described a spray technique using PMDI products to enhance thestrength of the corrugated medium of container board prior to thelamination of external facings. Clearly the prior art appreciated theproblem of impregnating a multi-ply laminate after assembly. Park et alin U.S. Pat. No. 5,580,922 attempted to overcome the problem of deepcross-section cure by the addition of a catalyst system. J. Maxwell inU.S. Pat. No. 5,729,936 issued in Mar. 24, 1998 employed removable rodsthat provided conduits for the drying of the compressed slurry.

[0011] The problem of flame retardancy has been confronted in manypatents related to building panels. Some include U.S. Pat. Nos.5,729,936; 5,715,637; 6,368,529 and 5,880,243. The last mentioned byPark et al in U.S. Pat. 5,880,243 issued Mar. 9, 1999 detailed trialswere described in the quest of flame retardancy in lignocellulosecomposites. Herein the virtues of mono-ammonium phosphate, diammoniumphosphate, halogenated phosphates, borates aluminum trihydrate andantimony oxide were explored. Commercially prepared (brand name) flameretardants were also documented. The volume of plastics in the solidwaste is approximately 25%. This represents 90% of the total volume ofplastics actually produced and can be regarded as a considerable drainon the non-renewable resource base, mankind, governments and theenvironment. The recycling of thermoplastics has been integral to theindustry from its inception. Early recycling involved the fragmentationand reuse of factory generated scraps. Later techniques involvedheating, compaction, shredding and granulation. These methods extendedthe range of products developed from recycled post-consumerthermoplastics. New products included fabrics, carpets, householddurables and packaging. Lately research has been aimed at efficientmethods of identifying, sorting and separation of post consumerthermoplastics. Sommer et al in U.S. Pat. No. 6,313,423 issued Nov. 62001, applied Raman Emission Spectroscopy to identify and sort Postconsumer thermoplastics. Allen III et al in U.S. Pat. No. 6,335,376issued Jan. T 2002, describes a method of separation of post consumerthermoplastics by a process of density differential alteration. What isnot disclosed in the prior art is the non-destructive remanufacture ofpanels from cardboard as well as the application of resin solutionsrecovered from post consumer thermoplastics as the impregnant for thefabrication and decoration of said panels. The methods disclosed in thisinvention therefore regards the cardboard sheetstock as an intermediateper form whose characteristics are exploited in the impregnation dryingand lamination stages of panel fabrication

SUMMARY OF INVENTION

[0012] The invention herein described is directed to new and usefullight weight lignocellulosic fibre-polymer sheeted products. The sheetedproducts may be fabricated to form partitions walls roof, ceiling,insulation, floors and furniture of domestic (permanent and relocatable)recreational, agricultural, marine and commercial buildings Cardboardsheet stock (post consumer or ex-factory) are inspected for openness ofthose spaces formed by their corrugated interior. Where edges aredamaged these are cut with a sharp instrument to expose the entrance tothe interior columnar spaces. Constrictions in the columns may also beremoved by cutting away sections along which folding was done to formboxes. Dents and fractured sections may also be similarly trimmed toexpose the interior columnar spaces. Sections breached by staples mayalso be removed, since they will obstruct the drenching/impregnationprocess. Cardboard sheet stock so prepared are neatly stacked, clampedand oriented such that the columnar spaces are oriented in the verticalplane. Resin solution recovered from post consumer thermoplastic is thenpoured into the vertically oriented columnar spaces until the excessflows out at the lower openings of said columnar spaces. The stack isthen laid horizontally and allowed to dry. Drying may be achieved bywheeling into a kiln, or wrapping in a plastic or leatherette sheetunder which hot air is circulated. Microwave and RF radiation are alsofeasible methods. The addition of a compatible exothermic catalystsystem to the resin solution immediately prior to drenching is also afeasible drying technique. Other additives may be added to the drenchingresin solution complex including insecticides, flame retardants, waterproofing agents and wood preservatives. Where cardboard sheet stockdemonstrates large bore columnar spaces, lamination and lay-up may bedone prior to drench/impregnation. The viscosity of the resin solutionis adjusted to the diameter of the columnar spaces in the cardboardstock prepared for impregnation. An adequate drench does not result insaturation of the surface layers of the cardboard sheet stock and theycontinue to be separable by gentle delamination efforts after drying.Repeated drenching may be done to achieve a threshold impregnation.These successive drenches, however, must not clog the columnar spaces.

[0013] The clamping technique must be such that the individual cardboardsheets are tightly packed prevention resin flows about their externalsurfaces. The dried impregnated cardboard sheet stock is then laid up tothe desired form and thickness. This is done by roller application ofadhesive followed bv superposing. Where impregnated sheets vary in sizethey may be staggered to prevent joint alignment. Plies should be ofuniformed thickness, cutouts may be done at this stage for doors,windows, roof rafters, fastening metal inserts, plumbing, electrical,heating and margins for mated joints. The completed lay-up is clampedthen dried by directing hot air through the open columnar spaces asdescribed above. Clamping must achieve contact pressure alone. This canbe still considerably higher than that applied during post impregnationdrying due to the increased compressive loading capability of theimpregnated corrugated units within. At threshold production volumes,vacuum evaporation can be used to achieve solvent condensation andrecovery. Scale economies may be feasible during the drying processusing such solvent condensation techniques. Panels destined for use ashigh load bearing units are encased in wire mesh of appropriate density.The wire mesh is secured using twisted wire connected to either sidethrough drilled holes. Such panels are transported positioned andfinished using portland cement mortar. Delamination guards are installedby deploying nuts and bolts with washers of appropriate diameters overthe exposed superficial face of the cured panel but before lay up of theexternal crust. Nuts and bolts are introduced to secure metal insertsand partially function as delamination guards simultaneously.

[0014] Panels destined for low and moderate load bearing applicationsmay be surface finished by a range of optional treatments. These optionsare arranged below in ascending order of sophistication.

[0015] 1. The outer surfaces are strengthened using several laminationsof paper. These panels may then be painted using, decorative coatingformulated from resin solutions recovered from post consumerthermoplastics.

[0016] 2. The outer surfaces are laminated with a fabric gauze ofappropriate texture and porosity using an adhesive formulated usingresin solutions recovered from post consumer thermoplastics.

[0017] 3. Coarse fabric gauze is laid up on the outer surfaces using anadhesive formulated from resins recovered from post consumerthermoplastics. A 4 mm layer of Portland cement mortar is applied tosmoothness. In this method delamination guards may be located after thecoarse fabric gauze has been laid up to also assist in the securing ofthe gauze itself

[0018] 4. The cured panel may also be finished using a polymeric mortarconsisting of resin solution recovered from post consumer thermoplasticschopped fibre, micronized mineral particles and small particle buildingaggregates. When partly cured these lay-ups may be planed using a freshmix of easy flowing polymeric cement mortar. Planing may be done usinghand float, draw board, guided edges or rotary devices. Where indicatedflame retardants may be included in this polymeric cement mortar.

[0019] 5. The cured panel may also be finished after securing a fibremat to the outer surfaces using polymeric adhesives as described above.Delaminating guards may then be deployed strategically. Upon drying 8 mmof Portland cement mortar is applied to smoothness.

[0020] Dried panels destined for use as roof panels require furthervariations. These are laid up to half of their final thickness. A layerof wire mesh of an appropriate density is then laid up along with aslick of polymeric cement sufficient to slightly cover the wire mesh.The other plies are laid up and cured. Alternatively the other half ofthe panel may be superposed upon the wire mesh/polymeric cementsecondary core. Upon curing ribs are attached corresponding to raftersand purlins of conventional roofing. The interval used between theseribs must match recesses left on the relevant upright wall panels. Theseribs are formed by cutting off suitably sized (5-8 mm)×(16-21 m)×L fromcured panels. The rafter sections are then secured to the roof panel bypolymeric adhesive cements and fabric gauze. Dedicated purlin elementsmay be fabricated with an internal reinforcement of wire mesh ofappropriate density. As described above a slick of polymeric cement mustalso accompany the reinforcing wire mesh.

[0021] The exposed surface of the roof panel is thickened with two tothree laminations of paper and polymeric adhesive. Alternatively afabric gauze of suitable density and weatherability may be applied andsecured with a polymeric adhesive. Voids created at the surface wheresheets are joined may be solidified using a polymeric cement mortar orputty. Upon drying a fabric gauze is also secured to said exposedsurface using a polymeric adhesive. A pigmented decorative coating isapplied. Said decorative coating is formulated from resin solutionformulated from post consumer thermoplastics.

[0022] The dry cardboard panel may also be used in the fabrication offurniture. In this application it can replace some classes of compressedcomposite boards in countertops, troughs, table tops, bed heads,ceilings, sidings and awnings. Where high stress joints are contemplatedthe aeroboard may be strengthened locally by injection of quick settingpolymer cements into the columnar air spaces and cutouts around inserts.Dimensional stability may also be enhanced by attachment to lengths oftimber. Such furniture can be surfaced finished using veneers coatingsand laminations.

[0023] The recovery of resin solutions from post consumer thermoplasticshas been the source of binders for the fabrication of panels in thisinvention. In so doing an attempt is made to utilize two classes ofbulky wastes simultaneously into new and useful remanufactured products.Of the polymer species recovered polystyrene foam is the most abundant;and the most soluble. For commercial recovery of polystyrene solutionfrom polystyrene foam (expanded polystyrene) the peculiarities of itsstructure had to be observed and exploited. Upon exposure to potentorganic solvents polystyrene foam dissolves rapidly. If the foamspecimens are added to the solvent in a container rapid dissolutionbegins. The low specific gravity of the polystyrene foam causesflotation at the surface of the solvent. The dissolution slows downprogressively as the solution at the base of the floating foam massthickens. The specific gravity of the floating gel is reduced by theentrapment of pockets of liberated blowing agent from the collapsingclosed cells of polystyrene foam. The increasingly viscous gel becomes amechanical barrier between relatively pure and unsaturated solvent belowit and the intact mass of expanded foam above it (the viscous gel).These events militate against efficient application of immersion as aneffective and viable method for commercial recovery of resin solutionfrom post consumer polystyrene foam.

[0024] In this invention the foam digester is applied to overcome thedifficulties outlined above. The key element in the superiorproductivity of the foam digester is the dispersing of the solvent fromlocations above the charge of polystyrene foam specimens. The dispersionof the solvent from above the foam specimens allows the escape of theblowing agent from the collapsing closed cells. These pockets of blowingagent escape directly through the surface of films of highly unsaturatedresin solution flowing over the unstable surface of dissolving foamspecimens. The moving film of solution does not allow strong surfacetension to be achieved due to the effervescence of migrating pockets ofblowing agent. Pockets of blowing agents are also liberated byabandonment due to the downward movement of the solution. Theeffervescence of the blowing agent also lubricates the downward flow ofthe resin solution. Further, continuous dilution of the resin solutionso formed allows continued solvent attack on the closed cells at thesurface of intact polystyrene foam specimens. Said dilution results fromthe continuing release of solvent from solvent dispenser located abovethe polystyrene charge.

[0025] Polystyrene foam specimens at the lower regions of the chargealso benefit from good wetting out and surface cling achieved by theincreasingly viscous solution in its downward flow. Penetration is alsoachieved by the upward displacement of the blowing agent and theentrapment of solvent in the freshly opened empty cells.

[0026] The control valve supplying the dispersion system must thereforebe adjusted to allow a final solution that can flow readily intocollection drums. Accumulated solution is drained off periodically.Solvent flow adjustments are influenced by the foam density, the solventpotency and the height of the polystyrene foam charge in the digestionchamber.

[0027] Solvent action in the foam digester is therefore rapid andproductive. Any solvent pump in use is adjusted with the help of avalve-controlled return line. Solvent delivery rate is a function offrictional losses based on column height, initial pump pressure,tank-to-pump frictional losses and the pressure deflation created bysetting variations at the two control valves. Solvent delivery at thedispenser is the residual pressure occasioned by these adjustments.

[0028] The dissolution of other plastics is not as rapid as obtains inpolystyrene foam. The method for recovering other species thereforeinvolves immersion in solution vats containing solvents of assessedpotency. The table below matches various polymer species to theirrespective solvents. POLYMER TYPE SOURCES SOLVENTS PolystyreneRefrigerator liners, Toluene, Acetone television and radio cabinetsPolymethyl- Television cabinets, Acetone, MEK (Methyl metacrylate toys,signs, refrig- Ethyl Ketone) solvent erator accessories, automobileaccessories Polyvinyl Chlo- Pipes, floor tiles, Acetone, MEK (Methylride floor covering, Ethyl Ketone) solvent, computer monitor, sulfolane,dioxan, cabinets, domestic perchlor ethylene, plastic sheeting nitromethane, 3- sulphonolanyl, ethyl ether, m-chloraniline PolyethyleneBottles, tanks, bags, Decalin, tetralin, film, tetrachlorethanePolyesters Fabrics Phenol Meta-cresol orthochlor phenol Flame ResistantComputer housing fax Acetane, MEK (Methyl High Impact machines,photocopiers, Ethyl Ketone) solvent Polystyrene scanners (FR-HIPS)Polystyrene foam Insulation, packaging Toluene Acrilonitrile Buta-Computer housings, MEK solvent, acetane, diene refrigerator linersmethylene, chloride Styrene (ABS) copolymers. Acrilonitrile Sty-Computer cases, fax Acetone, MEK solvent rene, Acrilonitrile machines,photocopiers, (ASA) copolymer, housings ignition resistance (IR). Flameresistant Computer housings for Acetone, MEK solvent polycarbonatemachines housings, (ABS) FR photocopier housing PC/ABS

[0029] The resin solutions recovered from these consumer thermoplasticwastes are used in the preparation of adhesives, polymeric cements,sealants and pigmented coatings for the prefabricated panels. Resinsolutions recovered from PVC wastes and the cases of computer monitorsIR and FR (ABS, ASA, PC/ABS) confer flame retardancy to preparations ofwhich they are a component and are particularly valued for this purpose.These flame retardant components are used in conjunction with otherflame retardants such as boron, ammonium, phosphates and halogenatedcompounds mentioned earlier.

[0030] Water soluble flame retardants can be applied to the cardboardsheet stock before impregnation as a drench. Stacking, drenching anddrying may be done similar to the methods described for resin solutionimpregnatioli. Water insoluble flame retardants are dispersed intoimpregnating solution, adhesives and polymeric cements used in thefabrication of the cardboard panels.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 An array of cardboard specimen section.

[0032]FIG. 2 Depicts a section of aeroboard panel with an inner cone ofresin laminated cardboard (aeroboard) without an outer crust.

[0033]FIG. 3 Depicts a section of prefabricated building panel with aninner core of resin impregnated laminated cardboard (aeroboard) with itsouter surface thickened with laminations of paper.

[0034]FIG. 4 Depicts a section of aeroboard panel with its outer surfacefinished with resin impregnated cloth.

[0035]FIG. 5 Depicts a section of aeroboard panel with its outer surfacefinish with a polymeric cement mortar.

[0036]FIG. 6 Depicts a section of aeroboard with its outer surfacecovered with a mat of random fibres.

[0037]FIG. 7 Depicts a section of aeroboard with its outer surfacecovered with a mat of random fibres with delamination guard screwsinstalled.

[0038]FIG. 8 Depicts section of aeroboard panel with its outer surfacecovered with an adhered random fibre mat, installed delamination guardbolts and a 10 mm overlay of Portland cement mortar.

[0039]FIG. 9 Depicts a section of aeroboard panel with its outer surfacecovered with an adhered coarse fabric gauze, installed delaminationbolts reinforcement and a 10 cm layer of portland cement mortar.

[0040]FIG. 10 Depicts a section of areoboard panel with its outersurface covered with an adhered coarse fabric gauze, installeddelamination bolts, fastened steel wire mesh reinforcement and a 3 cmlayer of portland cement mortar.

[0041]FIG. 11 Depicts a section of aeroboard panel with a secondary coreof wire mesh and polymeric cement mortar designed for use as roofdecking.

[0042]FIG. 12 Depicts a section of aeroboard roof decking with inneradhered purlins (rafter) and outer fabric lamination.

[0043]FIG. 13 Depicts a section of aeroboard panel with the columnar airspaces oriented to form the thickness of the panel.

[0044]FIG. 14 Depicts a section of aeroboard panel with the columnar airspaces oriented to a bias alternating pattern.

[0045]FIG. 15 Depicts a section of aeroboard panel with the columnar airspaces to form the thickness of the panel and completely filled with apolymeric cement to present a honeycomb pattern.

[0046]FIG. 16 Depicts a section of aeroboard purlin or rafter elementwith a secondary core consisting of steel wire mesh embedded inpolymeric cement jacket.

[0047]FIG. 17 Depicts the superficial distribution of delamination guardbolts on an aeroboard panel.

[0048]FIG. 18 (a) Depicts a top view of a flanged fastening metalinsert.

[0049]FIG. 18 (b) Depicts a section of a flanged fastening metal insert.

[0050]FIG. 19 (a) Depicts a top view of a crossed fastening metalinsert.

[0051]FIG. 19 (b) Depicts a section of a crossed fastening metal insert.

[0052]FIG. 20 (a) Depicts an isometric view of a metal insert withu-shaped receptacle.

[0053]FIG. 20 (b) Depicts a top view of a metal insert with u-shapedreceptacle.

[0054]FIG. 21 (a) Depicts a section of aeroboard showing installedplumbing elements.

[0055]FIG. 21 (b) Depicts a section of aeroboard showing installedelectrical elements.

[0056]FIG. 22 (a) Depicts a section of aeroboard panel attached to afoundation using u-shaped flanged receptacle.

[0057]FIG. 22 (b) Depicts a section of aeroboard panel attached to afoundation using crossed steel bar insert.

[0058]FIG. 22 (c) Depicts a section of aeroboard panel attached to afoundation using side-lapped steel wire mesh extensions.

[0059]FIG. 23 Depicts a section of aeroboard panel attached to apre-existing concrete wall.

[0060]FIG. 24. Depicts aeroboard panel joint u sing groove and tonguearrangement.

[0061]FIG. 25 Depicts a connection of two aeroboard panels using weldedextensions of steel inserts.

[0062]FIG. 26 Depicts a lap joint between two aeroboard panel sections.

[0063]FIG. 27 Depicts a joint between two aeroboard panels using apattern of interdigitation.

[0064]FIG. 28 Depicts an aeroboard using overlap of embedded steel wiremesh.

[0065]FIG. 29 Depicts attachment of an aeroboard roof decking to a wallformed from aeroboard panel.

[0066]FIG. 30 Stereogram depicting the location of a flanged metalinsert within an aeroboard lamination.

[0067]FIG. 31 Depicts a side elevation of the foam digester with thereciprocating hopper in the lowered position.

[0068]FIG. 32 Depicts a side elevation of the foam digester with thereciprocating hopper in the raised position.

[0069]FIG. 33 Depicts various views of the solvent dispenser assembly ofthe foam digester.

[0070]FIG. 34 (a) Depicts the top view of the foam digester.

[0071]FIG. 34 (b) Depicts the top view of the foam digester with acut-away section showing the location of the solvent dispenser.

[0072]FIG. 35 Depicts a sectional view of a solvent tank containing asuspended stack of post consumer thermoplastic.

DETAILED DESCRIPTION OF THE INVENTION

[0073] The alignment of the corrugations parallel to the long axis ofthe panel typically confers load bearing capability in the long axis.FIG. 2 shows the consequent honey comb pattern of corrugations at thepanel end. FIG. 14 shows a contrasting pattern of bias ply orientationapplicable where higher stress loads are contemplated in lociperpendicular to the long axis of the panel. FIG. 13 demonstrates yetanother preferred embodiment with the columnar air spaces oriented inthe short axis to achieve highest compressive strength against stressesperpendicular to the long axis. This is best demonstrated inapplications where the panel is itself supported as in floorings andwall veneers. FIGS. 3 through II demonstrates the wide range of optionsavailable for the surface crust finish on the aeroboard panels. FIG. 10with its steel wire mesh and 3 cm thick outer crust is capable ofconsiderable load bearing capability. The highest compressive strengthmay be achieved using the design shown in FIG. 15. In this preferredembodiment the compressive strength is trebled by the orientation of thecorrugations in the short axis and the densification of the completedpanel with an aggregate containing polymeric cement mortar. Thestrategic distribution of delamination guard bolts is shown in FIGS. 17,22, 23, 25 and 30. FIGS. 18,19,20,22 and 23 show the versatility of thedevices available for fastening the aeroboard panels to themselves andother structures.

[0074]FIGS. 25 through 29 all show methods for joining aeroboard panelto one another FIG. 29 is a particularly formidable joint involvingelement oriented in several plane. The details of the foam digester inFIGS. 31 through 33 help to clarify the structure and operation of thedevice. The reciprocating hopper (47) allows the foam feedstock to beloaded at ground level and then raised to the digestion chamber trapdoor. The foam stock pile slides against the outer face of the digestionchamber and cascades inward upon reaching the level of the trap door.Remnants slide downwards along the angled floor of the reciprocatinghopper (47). The sidewalls of the reciprocating hopper are hingedforming a recoilable basket which flaps outward to allow comfortableloading. It is secured during travel.

[0075] In FIG. 42 is shown the process in which complex shapes aredimembered into sheet and non-sheet fragment spaces to facilitateliberal contact with the solvent bath. This technique avoids snoballingand gelation which prevents the continued solvent penetration andhomogenous dispersion of the target PCTP solute.

What is claimed is 1) A prefabricated panel designed to fit togetherwith other panels of the same design and conventional building materialsto form walls, floors, ceilings, roofs insulation slabs, partitions andfurniture of buildings comprising an inner aerated core made fromlaminations of cardboard (corrugated container board) that have beenimpregnated superficially and internally by resin/solutions recoveredfrom post consumer thermoplastics as the impregnant. Said lamination isachieved by the application of adhesives recovered from post consumerthermoplastics and contact pressure alone which allows the sustainedcolumnar structure of the corrugated cardboard elements. 2) Aprefabricated panel as claimed in claim (1) wherein one or moreadditional elements selected from the group consisting of electrical,plumbing and attachment components are inserted in said core during thelamination process by cut-outs and lateral displacement of cardboardelements. 3) Additional elements as claimed in claim (2) may have theirtolerances reduced by the application of polymer cements containingparticulates and fibres. 4) A prefabricated panel as claimed in claim(1) wherein one or more additional ingredients selected from a groupconsisting of insecticides, waterproofing agents, anti-fungal agents andflame retardants are added to the impregnant, laminating adhesive or thecrust forming polymer cement mortar. 5) A prefabricated panel as claimedin claim (1) wherein the core may be made receptive to the attachment ofPortland cement mortar by the attachment of an interface consisting offabric gauze, fibres, fibre mats adhered to the external cardboard coresurface. 6) A prefabricated panel as claimed in claim (5) wherein theouter core surfaces are thickened by lamination of resin-impregnatedpaper or fabric as a surface finish or to increase surface impactresistance. 7) A prefabricated panel as claimed in claim (6) wherein thesurface is painted using cementitious coatings formulated from resinsolutions recovered from post consumer thermoplastics, pigments,particulates and plasticisers. 8) A prefabricated panel as claimed inclaim (1) wherein wire mesh including B.R.C may be fastened to the outerfaces of the cardboard core using connecting stands of wire insertedthrough perforations in the cardboard core; said wire mesh receives andstrengthens Portland cement mortar crusts; cardboard cores with theirattached steel mesh may be transported to the construction site andfixed before lay-up of the Portland cement mortar. 9) A prefabricatedpanel as claimed in claim (1) wherein a single ply of steel meshtogether with a polymer cement mortar forms the innermost layer of thecardboard core by its entrapment between two sections possessing halfthe dimensional thickness of the prospective panel core. 10) Aprefabricated panel as claimed in claim (1) wherein the outer crustconsists of polymer based mortars formulated from resin solutionsrecovered from post consumer thermoplastics and micronised particulates,fibres and aggregates. 11) A prefabricated panel as claimed in claim (9)wherein the external crust are formed using methods described in claim(10) mutually excluding methods described in claim (8). 12) Aprefabricated panel as claimed in claim (1) wherein the spaces fordoors, archways windows, air-condition, recess for roof rafters units,metal inserts, exhaust fans are excluded during lamination or may be cutout after lamination. 13) A prefabricated panel as claimed in claim (1)wherein the columnar spaces created by the corrugated elements withinthe cardboard sheetstock are inspected for openness and slicedtransverse to the column axis using a sharp cutting instrument tofacilitate internal distribution of the post consumer thermoplasticresin solution, evaporation of the solvent and the circulation of hotair to accelerate solvent evaporation. 14) A prefabricated panel asclaimed in claim (1) wherein the cardboard sheetstock as prepared inclaim (13) are stacked and clamped superposed with the corrugatedcolumnar spaces oriented vertically thereby facilitating theintroduction and dissemination of the thermoplastic resin solutionimpregnant by internal drenching, gravity flow and capillary action. 15)A prefabricated panel as claimed in claim (14) wherein drenching iscontinued until excess resin drains out at the lower end of thevertically oriented cardboard stack 16) A prefabricated panel as claimedin claim (15) wherein hot air is forced through the columnar airspacesof the impregnated cardboard sheetstock to accelerate solventevaporation and the formation ofa stiff fibre polymer matrix. 17) Aprefabricated panel as claimed in claim (15) wherein said processes arerepeated until a threshold polymer saturation is achieved characterizedby optical changes, improved impact strength without columnar spaceocclusion. 18) A prefabricated panel as claimed in claim (15) whereinresin viscosity is adjusted based on the assessed porousity of thecardboard sheetstock, the polymer species present in the impregnant andthe diameter of the columnar spaces. 19) A prefabricated panel asclaimed in claim (1) wherein the labyrinth of interconnected microsporesand longitudinal columns present in the cardboard sheetstock provides atemplate for the expansion of the polymer impregnant. 20) Aprefabricated panel as claimed in claim (1) wherein the longitudinalcolumnar spaces of fully cured panels may be partially filled with apolymer cement to enhance load bearing characteristics and the receiptof surface amendments. 21) A prefabricated panel as claimed in claim (1)wherein bolts are introduced at strategic points on the superficialaspect to secure metal inserts and inhibit delamination stresses. 22) Aprefabricated panel as claimed in claim (1) wherein ribs are attached atintervals to function as rafters or purlins for roof construction. 23) Aprefabricated panel as claimed in claim (22) wherein a steel mesh isincorporated in both rafter elements and the main panel body by methodsdescribed in claim (9). 24) A prefabricated panel as claimed in claim(1) wherein joining may be facilitated by lap joints, interdigitation ofmated edges and the welding of metal abutments that may extend from thefastened metal inserts ofjuxtaposed panels. 25) A prefabricated panel asclaimed in claim (1) wherein the resin solutions and adhesives areselected individually or severally from a group of post consumerthermoplastics that include polystyrene foam, polystyrene (unexpanded),polymethyl methacrylate, celulosics, polyvinyl chloride, polyurethane,asphalt, flame retardant high impact polystyrene (FR) HIPS, (FR) ABS(Acrilonitrile butadiene styrene), (FR) Acrilonitrile StyreneAcriloniltrile (ASA), Flame Resistant (PC/ABS) (Polycarbonate/ABS) andIgnition resistant, polycarbonate ABS (IRPC/ABS). 26) A prefabricatedpanel as claimed in claim (1) wherein solvents, dispersants and swellingagents are selected individually or in combination from a groupcomprising, toluene, acetone, methylethyl ketone (M.E.K), methylenechloride, methylene trichloride, sulfolane, ethylene glycol, amylacetate, propylene glycol, methanol, diesoline, propylene carbonate,methylene dichloride, dioxan, decalin, tetralin, meta cresol, tetrachlorethane, orthochlorphenol, trichlorphenol, ethylene-m-chloraniline,3-sulphonolanyl ethyl ether, phenol, nitromethane and kerosene. 27) Amethod for commercial recovery of resin solution from polystyrene foamusing apparatus called the foam digester comprising: (a) A largecapacity digestion tank into which polystyrene foam is fed from a stockpile. (b) A solvent distribution system made from perforated tubesmounted above the hopper which directs a solvent shower over thepolystyrene charge in the digestion tank. (c) A funnel-shaped lowerfloor in the digestion tank collects the resin solution, whichaccumulates with increasing viscosity after its downward flow anddissolution through the resident polystyrene foam charge. (d) A pumpwhich delivers the solvent to the distribution system. (e) The solventflow rate is adjusted by control valves present on the solvent supplyline and the solvent return line. (f) Collected resin solution isremoved periodically. (g) A vertical reciprocating hopper recharges thepolystyrene foam charge within the digestion chamber at meteredintervals assessed by the operator. (h) A hinged recoil able innerbasket which is released when the vertical reciprocating hopper is atrest in the lowered position thereby facilitating loading. (i) Anextended side wall which retains the polystyrene foam feed stock fromescaping from the open side of the recoilable inner basket of thereciprocating hopper. (j) The polystyrene foam feedstock slides into thedigestion chamber along the slanting floor of the reciprocating hopperwhen it becomes aligned with the trap door opening of the digestionchamber during the upper extremity of its vertical travel. (k) Thereciprocating vertical locus of travel of the reciprocating hopper isfacilitated by linkages to a drive sprocket, chain, a concentric slavesprocket and gear assembly and a mated serrated bar. 28) The recovery ofresin solutions from Postconsumer thermoplastics (PCTP) by simpleimmersion in a potent solvent bath 29) The method of claim 28 whereinthe PCTP material is coarsely pulverized to achieve volume reductionbefore simple immersion. 30) The method of claim 28 wherein the solventbath is charged with the addition 20% styrene solution by volume topromote homogenous dispersion of highly cohesive PCTP feedstock solutes31) The methods of claim 30 wherein an inert, micronised mineralparticle forms 20% by volume suspended in the solvent to promotemechanical dispersion of highly cohesive PCTP solute feedstock. 32) Themethod of claim 31 wherein intermittent agitation is applied using arotary or oscillating device. 33) The method of claim 31 wherein adispersion of wax, 10% by volume is added to the solvent bath toplasticise the dissolved PCTP feedstock solute. 34) The method of claim31 wherein dispersion is promoted using a rotary device to acceleratecollision between the surface of PCTP feedstock and swirling inertmineral particles. 35) The method of claim 10 wherein the formulation ofadhesives, binders, coatings and cements that specifically exploits theflame retardant and ignition resistant products recovered from solutionsof post consumer: P.V.C, FRHIPS, FR/ABS, PC/ABS, IR/HIPS, PVC/ABS 36)The method of claim 10 wherein the solvent is selected uniquely orseverally in cocktails from Schedule of Solvents and Corresponding PCTPpresented below. Polymer Species Sources Solvents 1 High impact Poly-Refrigerator door liners, Acetone Methyl Ethyl styrene HIPS televisioncabinets Ketone (MEK) Solvent Polymelthyl- Television cabinets, toysAcetone, MEK solvent metacrylate signs, refrigerator accessories, automobile accessories Polyvinyl Chlo- pipes, floor tiles, Sulfolane dioxanride corrugators monitors perchlorethylene cabinets floor nitromethane,3 - coverings sulphorolanyl ethyl ether, m - chloraniline Polyethylenebottles, tanks, bags, Decalin, tetralin film tetrachlorethane, tri chlorphenol, meta-cresol, ortho-chlorphenol Flame Retardant Computermonitors, fax Acetone, MEK solvent, HIPS machines, photocopiers toluenePolystyrene foam Insulation, packaging Toluene, Acetone Flame retardantComputer monitor Acetone Acrilonitrile Buta- housing MEK solvent dienestyrene methylene chlorine (FR/ABS) Flame resistant Computer monitorAcetone MEK solvent polycarbonate/ABS housings, fax machine, (FR PC/ABS)photocopiers Ignition Resistant Computer monitor ″ Acriloritrile-housings, fax machine, Styrene photocopiers Acriloritrile (IR/ASA)Ignition Resistant Computer monitor ″ High Impact housings, fax machine,Polystyrene photocopiers (IR/HIPS) FR PC/ABS Computer monitor ″housings, fax machine, photocopiers PVC/ABS Computer monitor SulfolaneAcetone housings, fax machine, MEK solvent photocopiers

37) The method of claim (28) wherein purposeful and strategicfragmentation and volume reduction of complex post consumerthermoplastic products by dismemberment into sheets and non-sheetfragments prior to their immersion into solvent baths. 38) The method ofclaim (28) wherein thermoplastic sheet fragments are stacked usingnon-sheet fragments as spacers to facilitate liberal surface contactwith the investing solvent bath. 39) The method of claim (28) whereinthe stacked and spaced thermoplastic sheets are suspended in a solventbath using wire or cordage. 40) The method of claim (28) wherein solventagitation is achieved by air bubbles delivered through perforations theat dorsal aspect of an air pressure hose located at the floor of theimmersion vat. 41) The method of claim (14) wherein the cardboard stackis immersed in the impregnant or alternatively the impregnant is forcedinto the columnar spaces under hydrodynanic pressure.